A z-test is a statistical test used to determine whether two population means are different when the variances are known and the sample size is large.

In this article, we will explore some of the theory behind the one sample t test, assumptions of the test, interpretation and a worked example.

The likelihood ratio test, the large-sample z-test, and the large-sample z*-test have been proposed to test for the equality of two intraclass correlation coefficients under unequal family sizes based ...

References on sample size calculations for randomized studies with a continuous response are abundant. The sample size is usually calculated from a simple two-sample $z$-test.